Glass bubbles having an average diameter of less than about 500 micrometers, also commonly known as “glass microbubbles”, “hollow glass microspheres”, or “hollow glass beads” are widely used in industry, for example, as additives to polymeric compounds. In many industries, glass bubbles are useful, for example, for lowering weight and improving processing, dimensional stability, and flow properties of a polymeric compound. Generally, it is desirable that the glass bubbles be strong to avoid being crushed or broken during processing of the polymeric compound, such as by high pressure spraying, kneading, extrusion, pultrusion, sintering, or molding (e.g., compression molding, injection molding, blow molding, roto-molding, thermoforming, and injection-compression molding).
Some processes have been described for achieving high strength glass bubbles. However, at least due to their great utility, new high strength glass bubbles continue to be desirable.